2 * SLUB: A slab allocator that limits cache line use instead of queuing
3 * objects in per cpu and per node lists.
5 * The allocator synchronizes using per slab locks and only
6 * uses a centralized lock to manage a pool of partial slabs.
8 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
12 #include <linux/module.h>
13 #include <linux/bit_spinlock.h>
14 #include <linux/interrupt.h>
15 #include <linux/bitops.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuset.h>
20 #include <linux/mempolicy.h>
21 #include <linux/ctype.h>
22 #include <linux/kallsyms.h>
29 * The slab_lock protects operations on the object of a particular
30 * slab and its metadata in the page struct. If the slab lock
31 * has been taken then no allocations nor frees can be performed
32 * on the objects in the slab nor can the slab be added or removed
33 * from the partial or full lists since this would mean modifying
34 * the page_struct of the slab.
36 * The list_lock protects the partial and full list on each node and
37 * the partial slab counter. If taken then no new slabs may be added or
38 * removed from the lists nor make the number of partial slabs be modified.
39 * (Note that the total number of slabs is an atomic value that may be
40 * modified without taking the list lock).
42 * The list_lock is a centralized lock and thus we avoid taking it as
43 * much as possible. As long as SLUB does not have to handle partial
44 * slabs, operations can continue without any centralized lock. F.e.
45 * allocating a long series of objects that fill up slabs does not require
48 * The lock order is sometimes inverted when we are trying to get a slab
49 * off a list. We take the list_lock and then look for a page on the list
50 * to use. While we do that objects in the slabs may be freed. We can
51 * only operate on the slab if we have also taken the slab_lock. So we use
52 * a slab_trylock() on the slab. If trylock was successful then no frees
53 * can occur anymore and we can use the slab for allocations etc. If the
54 * slab_trylock() does not succeed then frees are in progress in the slab and
55 * we must stay away from it for a while since we may cause a bouncing
56 * cacheline if we try to acquire the lock. So go onto the next slab.
57 * If all pages are busy then we may allocate a new slab instead of reusing
58 * a partial slab. A new slab has noone operating on it and thus there is
59 * no danger of cacheline contention.
61 * Interrupts are disabled during allocation and deallocation in order to
62 * make the slab allocator safe to use in the context of an irq. In addition
63 * interrupts are disabled to ensure that the processor does not change
64 * while handling per_cpu slabs, due to kernel preemption.
66 * SLUB assigns one slab for allocation to each processor.
67 * Allocations only occur from these slabs called cpu slabs.
69 * Slabs with free elements are kept on a partial list and during regular
70 * operations no list for full slabs is used. If an object in a full slab is
71 * freed then the slab will show up again on the partial lists.
72 * We track full slabs for debugging purposes though because otherwise we
73 * cannot scan all objects.
75 * Slabs are freed when they become empty. Teardown and setup is
76 * minimal so we rely on the page allocators per cpu caches for
77 * fast frees and allocs.
79 * Overloading of page flags that are otherwise used for LRU management.
81 * PageActive The slab is frozen and exempt from list processing.
82 * This means that the slab is dedicated to a purpose
83 * such as satisfying allocations for a specific
84 * processor. Objects may be freed in the slab while
85 * it is frozen but slab_free will then skip the usual
86 * list operations. It is up to the processor holding
87 * the slab to integrate the slab into the slab lists
88 * when the slab is no longer needed.
90 * One use of this flag is to mark slabs that are
91 * used for allocations. Then such a slab becomes a cpu
92 * slab. The cpu slab may be equipped with an additional
93 * lockless_freelist that allows lockless access to
94 * free objects in addition to the regular freelist
95 * that requires the slab lock.
97 * PageError Slab requires special handling due to debug
98 * options set. This moves slab handling out of
99 * the fast path and disables lockless freelists.
102 #define FROZEN (1 << PG_active)
104 #ifdef CONFIG_SLUB_DEBUG
105 #define SLABDEBUG (1 << PG_error)
110 static inline int SlabFrozen(struct page
*page
)
112 return page
->flags
& FROZEN
;
115 static inline void SetSlabFrozen(struct page
*page
)
117 page
->flags
|= FROZEN
;
120 static inline void ClearSlabFrozen(struct page
*page
)
122 page
->flags
&= ~FROZEN
;
125 static inline int SlabDebug(struct page
*page
)
127 return page
->flags
& SLABDEBUG
;
130 static inline void SetSlabDebug(struct page
*page
)
132 page
->flags
|= SLABDEBUG
;
135 static inline void ClearSlabDebug(struct page
*page
)
137 page
->flags
&= ~SLABDEBUG
;
141 * Issues still to be resolved:
143 * - The per cpu array is updated for each new slab and and is a remote
144 * cacheline for most nodes. This could become a bouncing cacheline given
145 * enough frequent updates. There are 16 pointers in a cacheline, so at
146 * max 16 cpus could compete for the cacheline which may be okay.
148 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
150 * - Variable sizing of the per node arrays
153 /* Enable to test recovery from slab corruption on boot */
154 #undef SLUB_RESILIENCY_TEST
159 * Small page size. Make sure that we do not fragment memory
161 #define DEFAULT_MAX_ORDER 1
162 #define DEFAULT_MIN_OBJECTS 4
167 * Large page machines are customarily able to handle larger
170 #define DEFAULT_MAX_ORDER 2
171 #define DEFAULT_MIN_OBJECTS 8
176 * Mininum number of partial slabs. These will be left on the partial
177 * lists even if they are empty. kmem_cache_shrink may reclaim them.
179 #define MIN_PARTIAL 2
182 * Maximum number of desirable partial slabs.
183 * The existence of more partial slabs makes kmem_cache_shrink
184 * sort the partial list by the number of objects in the.
186 #define MAX_PARTIAL 10
188 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
189 SLAB_POISON | SLAB_STORE_USER)
192 * Set of flags that will prevent slab merging
194 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
195 SLAB_TRACE | SLAB_DESTROY_BY_RCU)
197 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
200 #ifndef ARCH_KMALLOC_MINALIGN
201 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
204 #ifndef ARCH_SLAB_MINALIGN
205 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
209 * The page->inuse field is 16 bit thus we have this limitation
211 #define MAX_OBJECTS_PER_SLAB 65535
213 /* Internal SLUB flags */
214 #define __OBJECT_POISON 0x80000000 /* Poison object */
216 /* Not all arches define cache_line_size */
217 #ifndef cache_line_size
218 #define cache_line_size() L1_CACHE_BYTES
221 static int kmem_size
= sizeof(struct kmem_cache
);
224 static struct notifier_block slab_notifier
;
228 DOWN
, /* No slab functionality available */
229 PARTIAL
, /* kmem_cache_open() works but kmalloc does not */
230 UP
, /* Everything works but does not show up in sysfs */
234 /* A list of all slab caches on the system */
235 static DECLARE_RWSEM(slub_lock
);
236 LIST_HEAD(slab_caches
);
239 * Tracking user of a slab.
242 void *addr
; /* Called from address */
243 int cpu
; /* Was running on cpu */
244 int pid
; /* Pid context */
245 unsigned long when
; /* When did the operation occur */
248 enum track_item
{ TRACK_ALLOC
, TRACK_FREE
};
250 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
251 static int sysfs_slab_add(struct kmem_cache
*);
252 static int sysfs_slab_alias(struct kmem_cache
*, const char *);
253 static void sysfs_slab_remove(struct kmem_cache
*);
255 static int sysfs_slab_add(struct kmem_cache
*s
) { return 0; }
256 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *p
) { return 0; }
257 static void sysfs_slab_remove(struct kmem_cache
*s
) {}
260 /********************************************************************
261 * Core slab cache functions
262 *******************************************************************/
264 int slab_is_available(void)
266 return slab_state
>= UP
;
269 static inline struct kmem_cache_node
*get_node(struct kmem_cache
*s
, int node
)
272 return s
->node
[node
];
274 return &s
->local_node
;
278 static inline int check_valid_pointer(struct kmem_cache
*s
,
279 struct page
*page
, const void *object
)
286 base
= page_address(page
);
287 if (object
< base
|| object
>= base
+ s
->objects
* s
->size
||
288 (object
- base
) % s
->size
) {
296 * Slow version of get and set free pointer.
298 * This version requires touching the cache lines of kmem_cache which
299 * we avoid to do in the fast alloc free paths. There we obtain the offset
300 * from the page struct.
302 static inline void *get_freepointer(struct kmem_cache
*s
, void *object
)
304 return *(void **)(object
+ s
->offset
);
307 static inline void set_freepointer(struct kmem_cache
*s
, void *object
, void *fp
)
309 *(void **)(object
+ s
->offset
) = fp
;
312 /* Loop over all objects in a slab */
313 #define for_each_object(__p, __s, __addr) \
314 for (__p = (__addr); __p < (__addr) + (__s)->objects * (__s)->size;\
318 #define for_each_free_object(__p, __s, __free) \
319 for (__p = (__free); __p; __p = get_freepointer((__s), __p))
321 /* Determine object index from a given position */
322 static inline int slab_index(void *p
, struct kmem_cache
*s
, void *addr
)
324 return (p
- addr
) / s
->size
;
327 #ifdef CONFIG_SLUB_DEBUG
331 #ifdef CONFIG_SLUB_DEBUG_ON
332 static int slub_debug
= DEBUG_DEFAULT_FLAGS
;
334 static int slub_debug
;
337 static char *slub_debug_slabs
;
342 static void print_section(char *text
, u8
*addr
, unsigned int length
)
350 for (i
= 0; i
< length
; i
++) {
352 printk(KERN_ERR
"%8s 0x%p: ", text
, addr
+ i
);
355 printk(" %02x", addr
[i
]);
357 ascii
[offset
] = isgraph(addr
[i
]) ? addr
[i
] : '.';
359 printk(" %s\n",ascii
);
370 printk(" %s\n", ascii
);
374 static struct track
*get_track(struct kmem_cache
*s
, void *object
,
375 enum track_item alloc
)
380 p
= object
+ s
->offset
+ sizeof(void *);
382 p
= object
+ s
->inuse
;
387 static void set_track(struct kmem_cache
*s
, void *object
,
388 enum track_item alloc
, void *addr
)
393 p
= object
+ s
->offset
+ sizeof(void *);
395 p
= object
+ s
->inuse
;
400 p
->cpu
= smp_processor_id();
401 p
->pid
= current
? current
->pid
: -1;
404 memset(p
, 0, sizeof(struct track
));
407 static void init_tracking(struct kmem_cache
*s
, void *object
)
409 if (!(s
->flags
& SLAB_STORE_USER
))
412 set_track(s
, object
, TRACK_FREE
, NULL
);
413 set_track(s
, object
, TRACK_ALLOC
, NULL
);
416 static void print_track(const char *s
, struct track
*t
)
421 printk(KERN_ERR
"INFO: %s in ", s
);
422 __print_symbol("%s", (unsigned long)t
->addr
);
423 printk(" age=%lu cpu=%u pid=%d\n", jiffies
- t
->when
, t
->cpu
, t
->pid
);
426 static void print_tracking(struct kmem_cache
*s
, void *object
)
428 if (!(s
->flags
& SLAB_STORE_USER
))
431 print_track("Allocated", get_track(s
, object
, TRACK_ALLOC
));
432 print_track("Freed", get_track(s
, object
, TRACK_FREE
));
435 static void print_page_info(struct page
*page
)
437 printk(KERN_ERR
"INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
438 page
, page
->inuse
, page
->freelist
, page
->flags
);
442 static void slab_bug(struct kmem_cache
*s
, char *fmt
, ...)
448 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
450 printk(KERN_ERR
"========================================"
451 "=====================================\n");
452 printk(KERN_ERR
"BUG %s: %s\n", s
->name
, buf
);
453 printk(KERN_ERR
"----------------------------------------"
454 "-------------------------------------\n\n");
457 static void slab_fix(struct kmem_cache
*s
, char *fmt
, ...)
463 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
465 printk(KERN_ERR
"FIX %s: %s\n", s
->name
, buf
);
468 static void print_trailer(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
470 unsigned int off
; /* Offset of last byte */
471 u8
*addr
= page_address(page
);
473 print_tracking(s
, p
);
475 print_page_info(page
);
477 printk(KERN_ERR
"INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
478 p
, p
- addr
, get_freepointer(s
, p
));
481 print_section("Bytes b4", p
- 16, 16);
483 print_section("Object", p
, min(s
->objsize
, 128));
485 if (s
->flags
& SLAB_RED_ZONE
)
486 print_section("Redzone", p
+ s
->objsize
,
487 s
->inuse
- s
->objsize
);
490 off
= s
->offset
+ sizeof(void *);
494 if (s
->flags
& SLAB_STORE_USER
)
495 off
+= 2 * sizeof(struct track
);
498 /* Beginning of the filler is the free pointer */
499 print_section("Padding", p
+ off
, s
->size
- off
);
504 static void object_err(struct kmem_cache
*s
, struct page
*page
,
505 u8
*object
, char *reason
)
508 print_trailer(s
, page
, object
);
511 static void slab_err(struct kmem_cache
*s
, struct page
*page
, char *fmt
, ...)
517 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
520 print_page_info(page
);
524 static void init_object(struct kmem_cache
*s
, void *object
, int active
)
528 if (s
->flags
& __OBJECT_POISON
) {
529 memset(p
, POISON_FREE
, s
->objsize
- 1);
530 p
[s
->objsize
-1] = POISON_END
;
533 if (s
->flags
& SLAB_RED_ZONE
)
534 memset(p
+ s
->objsize
,
535 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
,
536 s
->inuse
- s
->objsize
);
539 static u8
*check_bytes(u8
*start
, unsigned int value
, unsigned int bytes
)
542 if (*start
!= (u8
)value
)
550 static void restore_bytes(struct kmem_cache
*s
, char *message
, u8 data
,
551 void *from
, void *to
)
553 slab_fix(s
, "Restoring 0x%p-0x%p=0x%x\n", from
, to
- 1, data
);
554 memset(from
, data
, to
- from
);
557 static int check_bytes_and_report(struct kmem_cache
*s
, struct page
*page
,
558 u8
*object
, char *what
,
559 u8
* start
, unsigned int value
, unsigned int bytes
)
564 fault
= check_bytes(start
, value
, bytes
);
569 while (end
> fault
&& end
[-1] == value
)
572 slab_bug(s
, "%s overwritten", what
);
573 printk(KERN_ERR
"INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
574 fault
, end
- 1, fault
[0], value
);
575 print_trailer(s
, page
, object
);
577 restore_bytes(s
, what
, value
, fault
, end
);
585 * Bytes of the object to be managed.
586 * If the freepointer may overlay the object then the free
587 * pointer is the first word of the object.
589 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
592 * object + s->objsize
593 * Padding to reach word boundary. This is also used for Redzoning.
594 * Padding is extended by another word if Redzoning is enabled and
597 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
598 * 0xcc (RED_ACTIVE) for objects in use.
601 * Meta data starts here.
603 * A. Free pointer (if we cannot overwrite object on free)
604 * B. Tracking data for SLAB_STORE_USER
605 * C. Padding to reach required alignment boundary or at mininum
606 * one word if debuggin is on to be able to detect writes
607 * before the word boundary.
609 * Padding is done using 0x5a (POISON_INUSE)
612 * Nothing is used beyond s->size.
614 * If slabcaches are merged then the objsize and inuse boundaries are mostly
615 * ignored. And therefore no slab options that rely on these boundaries
616 * may be used with merged slabcaches.
619 static int check_pad_bytes(struct kmem_cache
*s
, struct page
*page
, u8
*p
)
621 unsigned long off
= s
->inuse
; /* The end of info */
624 /* Freepointer is placed after the object. */
625 off
+= sizeof(void *);
627 if (s
->flags
& SLAB_STORE_USER
)
628 /* We also have user information there */
629 off
+= 2 * sizeof(struct track
);
634 return check_bytes_and_report(s
, page
, p
, "Object padding",
635 p
+ off
, POISON_INUSE
, s
->size
- off
);
638 static int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
646 if (!(s
->flags
& SLAB_POISON
))
649 start
= page_address(page
);
650 end
= start
+ (PAGE_SIZE
<< s
->order
);
651 length
= s
->objects
* s
->size
;
652 remainder
= end
- (start
+ length
);
656 fault
= check_bytes(start
+ length
, POISON_INUSE
, remainder
);
659 while (end
> fault
&& end
[-1] == POISON_INUSE
)
662 slab_err(s
, page
, "Padding overwritten. 0x%p-0x%p", fault
, end
- 1);
663 print_section("Padding", start
, length
);
665 restore_bytes(s
, "slab padding", POISON_INUSE
, start
, end
);
669 static int check_object(struct kmem_cache
*s
, struct page
*page
,
670 void *object
, int active
)
673 u8
*endobject
= object
+ s
->objsize
;
675 if (s
->flags
& SLAB_RED_ZONE
) {
677 active
? SLUB_RED_ACTIVE
: SLUB_RED_INACTIVE
;
679 if (!check_bytes_and_report(s
, page
, object
, "Redzone",
680 endobject
, red
, s
->inuse
- s
->objsize
))
683 if ((s
->flags
& SLAB_POISON
) && s
->objsize
< s
->inuse
)
684 check_bytes_and_report(s
, page
, p
, "Alignment padding", endobject
,
685 POISON_INUSE
, s
->inuse
- s
->objsize
);
688 if (s
->flags
& SLAB_POISON
) {
689 if (!active
&& (s
->flags
& __OBJECT_POISON
) &&
690 (!check_bytes_and_report(s
, page
, p
, "Poison", p
,
691 POISON_FREE
, s
->objsize
- 1) ||
692 !check_bytes_and_report(s
, page
, p
, "Poison",
693 p
+ s
->objsize
-1, POISON_END
, 1)))
696 * check_pad_bytes cleans up on its own.
698 check_pad_bytes(s
, page
, p
);
701 if (!s
->offset
&& active
)
703 * Object and freepointer overlap. Cannot check
704 * freepointer while object is allocated.
708 /* Check free pointer validity */
709 if (!check_valid_pointer(s
, page
, get_freepointer(s
, p
))) {
710 object_err(s
, page
, p
, "Freepointer corrupt");
712 * No choice but to zap it and thus loose the remainder
713 * of the free objects in this slab. May cause
714 * another error because the object count is now wrong.
716 set_freepointer(s
, p
, NULL
);
722 static int check_slab(struct kmem_cache
*s
, struct page
*page
)
724 VM_BUG_ON(!irqs_disabled());
726 if (!PageSlab(page
)) {
727 slab_err(s
, page
, "Not a valid slab page");
730 if (page
->offset
* sizeof(void *) != s
->offset
) {
731 slab_err(s
, page
, "Corrupted offset %lu",
732 (unsigned long)(page
->offset
* sizeof(void *)));
735 if (page
->inuse
> s
->objects
) {
736 slab_err(s
, page
, "inuse %u > max %u",
737 s
->name
, page
->inuse
, s
->objects
);
740 /* Slab_pad_check fixes things up after itself */
741 slab_pad_check(s
, page
);
746 * Determine if a certain object on a page is on the freelist. Must hold the
747 * slab lock to guarantee that the chains are in a consistent state.
749 static int on_freelist(struct kmem_cache
*s
, struct page
*page
, void *search
)
752 void *fp
= page
->freelist
;
755 while (fp
&& nr
<= s
->objects
) {
758 if (!check_valid_pointer(s
, page
, fp
)) {
760 object_err(s
, page
, object
,
761 "Freechain corrupt");
762 set_freepointer(s
, object
, NULL
);
765 slab_err(s
, page
, "Freepointer corrupt");
766 page
->freelist
= NULL
;
767 page
->inuse
= s
->objects
;
768 slab_fix(s
, "Freelist cleared");
774 fp
= get_freepointer(s
, object
);
778 if (page
->inuse
!= s
->objects
- nr
) {
779 slab_err(s
, page
, "Wrong object count. Counter is %d but "
780 "counted were %d", page
->inuse
, s
->objects
- nr
);
781 page
->inuse
= s
->objects
- nr
;
782 slab_fix(s
, "Object count adjusted.");
784 return search
== NULL
;
787 static void trace(struct kmem_cache
*s
, struct page
*page
, void *object
, int alloc
)
789 if (s
->flags
& SLAB_TRACE
) {
790 printk(KERN_INFO
"TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
792 alloc
? "alloc" : "free",
797 print_section("Object", (void *)object
, s
->objsize
);
804 * Tracking of fully allocated slabs for debugging purposes.
806 static void add_full(struct kmem_cache_node
*n
, struct page
*page
)
808 spin_lock(&n
->list_lock
);
809 list_add(&page
->lru
, &n
->full
);
810 spin_unlock(&n
->list_lock
);
813 static void remove_full(struct kmem_cache
*s
, struct page
*page
)
815 struct kmem_cache_node
*n
;
817 if (!(s
->flags
& SLAB_STORE_USER
))
820 n
= get_node(s
, page_to_nid(page
));
822 spin_lock(&n
->list_lock
);
823 list_del(&page
->lru
);
824 spin_unlock(&n
->list_lock
);
827 static void setup_object_debug(struct kmem_cache
*s
, struct page
*page
,
830 if (!(s
->flags
& (SLAB_STORE_USER
|SLAB_RED_ZONE
|__OBJECT_POISON
)))
833 init_object(s
, object
, 0);
834 init_tracking(s
, object
);
837 static int alloc_debug_processing(struct kmem_cache
*s
, struct page
*page
,
838 void *object
, void *addr
)
840 if (!check_slab(s
, page
))
843 if (object
&& !on_freelist(s
, page
, object
)) {
844 object_err(s
, page
, object
, "Object already allocated");
848 if (!check_valid_pointer(s
, page
, object
)) {
849 object_err(s
, page
, object
, "Freelist Pointer check fails");
853 if (object
&& !check_object(s
, page
, object
, 0))
856 /* Success perform special debug activities for allocs */
857 if (s
->flags
& SLAB_STORE_USER
)
858 set_track(s
, object
, TRACK_ALLOC
, addr
);
859 trace(s
, page
, object
, 1);
860 init_object(s
, object
, 1);
864 if (PageSlab(page
)) {
866 * If this is a slab page then lets do the best we can
867 * to avoid issues in the future. Marking all objects
868 * as used avoids touching the remaining objects.
870 slab_fix(s
, "Marking all objects used");
871 page
->inuse
= s
->objects
;
872 page
->freelist
= NULL
;
873 /* Fix up fields that may be corrupted */
874 page
->offset
= s
->offset
/ sizeof(void *);
879 static int free_debug_processing(struct kmem_cache
*s
, struct page
*page
,
880 void *object
, void *addr
)
882 if (!check_slab(s
, page
))
885 if (!check_valid_pointer(s
, page
, object
)) {
886 slab_err(s
, page
, "Invalid object pointer 0x%p", object
);
890 if (on_freelist(s
, page
, object
)) {
891 object_err(s
, page
, object
, "Object already free");
895 if (!check_object(s
, page
, object
, 1))
898 if (unlikely(s
!= page
->slab
)) {
900 slab_err(s
, page
, "Attempt to free object(0x%p) "
901 "outside of slab", object
);
905 "SLUB <none>: no slab for object 0x%p.\n",
910 object_err(s
, page
, object
,
911 "page slab pointer corrupt.");
915 /* Special debug activities for freeing objects */
916 if (!SlabFrozen(page
) && !page
->freelist
)
917 remove_full(s
, page
);
918 if (s
->flags
& SLAB_STORE_USER
)
919 set_track(s
, object
, TRACK_FREE
, addr
);
920 trace(s
, page
, object
, 0);
921 init_object(s
, object
, 0);
925 slab_fix(s
, "Object at 0x%p not freed", object
);
929 static int __init
setup_slub_debug(char *str
)
931 slub_debug
= DEBUG_DEFAULT_FLAGS
;
932 if (*str
++ != '=' || !*str
)
934 * No options specified. Switch on full debugging.
940 * No options but restriction on slabs. This means full
941 * debugging for slabs matching a pattern.
948 * Switch off all debugging measures.
953 * Determine which debug features should be switched on
955 for ( ;*str
&& *str
!= ','; str
++) {
956 switch (tolower(*str
)) {
958 slub_debug
|= SLAB_DEBUG_FREE
;
961 slub_debug
|= SLAB_RED_ZONE
;
964 slub_debug
|= SLAB_POISON
;
967 slub_debug
|= SLAB_STORE_USER
;
970 slub_debug
|= SLAB_TRACE
;
973 printk(KERN_ERR
"slub_debug option '%c' "
974 "unknown. skipped\n",*str
);
980 slub_debug_slabs
= str
+ 1;
985 __setup("slub_debug", setup_slub_debug
);
987 static void kmem_cache_open_debug_check(struct kmem_cache
*s
)
990 * The page->offset field is only 16 bit wide. This is an offset
991 * in units of words from the beginning of an object. If the slab
992 * size is bigger then we cannot move the free pointer behind the
995 * On 32 bit platforms the limit is 256k. On 64bit platforms
998 * Debugging or ctor may create a need to move the free
999 * pointer. Fail if this happens.
1001 if (s
->objsize
>= 65535 * sizeof(void *)) {
1002 BUG_ON(s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
|
1003 SLAB_STORE_USER
| SLAB_DESTROY_BY_RCU
));
1008 * Enable debugging if selected on the kernel commandline.
1010 if (slub_debug
&& (!slub_debug_slabs
||
1011 strncmp(slub_debug_slabs
, s
->name
,
1012 strlen(slub_debug_slabs
)) == 0))
1013 s
->flags
|= slub_debug
;
1016 static inline void setup_object_debug(struct kmem_cache
*s
,
1017 struct page
*page
, void *object
) {}
1019 static inline int alloc_debug_processing(struct kmem_cache
*s
,
1020 struct page
*page
, void *object
, void *addr
) { return 0; }
1022 static inline int free_debug_processing(struct kmem_cache
*s
,
1023 struct page
*page
, void *object
, void *addr
) { return 0; }
1025 static inline int slab_pad_check(struct kmem_cache
*s
, struct page
*page
)
1027 static inline int check_object(struct kmem_cache
*s
, struct page
*page
,
1028 void *object
, int active
) { return 1; }
1029 static inline void add_full(struct kmem_cache_node
*n
, struct page
*page
) {}
1030 static inline void kmem_cache_open_debug_check(struct kmem_cache
*s
) {}
1031 #define slub_debug 0
1034 * Slab allocation and freeing
1036 static struct page
*allocate_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1039 int pages
= 1 << s
->order
;
1042 flags
|= __GFP_COMP
;
1044 if (s
->flags
& SLAB_CACHE_DMA
)
1048 page
= alloc_pages(flags
, s
->order
);
1050 page
= alloc_pages_node(node
, flags
, s
->order
);
1055 mod_zone_page_state(page_zone(page
),
1056 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1057 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1063 static void setup_object(struct kmem_cache
*s
, struct page
*page
,
1066 setup_object_debug(s
, page
, object
);
1067 if (unlikely(s
->ctor
))
1068 s
->ctor(object
, s
, 0);
1071 static struct page
*new_slab(struct kmem_cache
*s
, gfp_t flags
, int node
)
1074 struct kmem_cache_node
*n
;
1080 BUG_ON(flags
& ~(GFP_DMA
| GFP_LEVEL_MASK
));
1082 if (flags
& __GFP_WAIT
)
1085 page
= allocate_slab(s
, flags
& GFP_LEVEL_MASK
, node
);
1089 n
= get_node(s
, page_to_nid(page
));
1091 atomic_long_inc(&n
->nr_slabs
);
1092 page
->offset
= s
->offset
/ sizeof(void *);
1094 page
->flags
|= 1 << PG_slab
;
1095 if (s
->flags
& (SLAB_DEBUG_FREE
| SLAB_RED_ZONE
| SLAB_POISON
|
1096 SLAB_STORE_USER
| SLAB_TRACE
))
1099 start
= page_address(page
);
1100 end
= start
+ s
->objects
* s
->size
;
1102 if (unlikely(s
->flags
& SLAB_POISON
))
1103 memset(start
, POISON_INUSE
, PAGE_SIZE
<< s
->order
);
1106 for_each_object(p
, s
, start
) {
1107 setup_object(s
, page
, last
);
1108 set_freepointer(s
, last
, p
);
1111 setup_object(s
, page
, last
);
1112 set_freepointer(s
, last
, NULL
);
1114 page
->freelist
= start
;
1115 page
->lockless_freelist
= NULL
;
1118 if (flags
& __GFP_WAIT
)
1119 local_irq_disable();
1123 static void __free_slab(struct kmem_cache
*s
, struct page
*page
)
1125 int pages
= 1 << s
->order
;
1127 if (unlikely(SlabDebug(page
))) {
1130 slab_pad_check(s
, page
);
1131 for_each_object(p
, s
, page_address(page
))
1132 check_object(s
, page
, p
, 0);
1135 mod_zone_page_state(page_zone(page
),
1136 (s
->flags
& SLAB_RECLAIM_ACCOUNT
) ?
1137 NR_SLAB_RECLAIMABLE
: NR_SLAB_UNRECLAIMABLE
,
1140 page
->mapping
= NULL
;
1141 __free_pages(page
, s
->order
);
1144 static void rcu_free_slab(struct rcu_head
*h
)
1148 page
= container_of((struct list_head
*)h
, struct page
, lru
);
1149 __free_slab(page
->slab
, page
);
1152 static void free_slab(struct kmem_cache
*s
, struct page
*page
)
1154 if (unlikely(s
->flags
& SLAB_DESTROY_BY_RCU
)) {
1156 * RCU free overloads the RCU head over the LRU
1158 struct rcu_head
*head
= (void *)&page
->lru
;
1160 call_rcu(head
, rcu_free_slab
);
1162 __free_slab(s
, page
);
1165 static void discard_slab(struct kmem_cache
*s
, struct page
*page
)
1167 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1169 atomic_long_dec(&n
->nr_slabs
);
1170 reset_page_mapcount(page
);
1171 ClearSlabDebug(page
);
1172 __ClearPageSlab(page
);
1177 * Per slab locking using the pagelock
1179 static __always_inline
void slab_lock(struct page
*page
)
1181 bit_spin_lock(PG_locked
, &page
->flags
);
1184 static __always_inline
void slab_unlock(struct page
*page
)
1186 bit_spin_unlock(PG_locked
, &page
->flags
);
1189 static __always_inline
int slab_trylock(struct page
*page
)
1193 rc
= bit_spin_trylock(PG_locked
, &page
->flags
);
1198 * Management of partially allocated slabs
1200 static void add_partial_tail(struct kmem_cache_node
*n
, struct page
*page
)
1202 spin_lock(&n
->list_lock
);
1204 list_add_tail(&page
->lru
, &n
->partial
);
1205 spin_unlock(&n
->list_lock
);
1208 static void add_partial(struct kmem_cache_node
*n
, struct page
*page
)
1210 spin_lock(&n
->list_lock
);
1212 list_add(&page
->lru
, &n
->partial
);
1213 spin_unlock(&n
->list_lock
);
1216 static void remove_partial(struct kmem_cache
*s
,
1219 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1221 spin_lock(&n
->list_lock
);
1222 list_del(&page
->lru
);
1224 spin_unlock(&n
->list_lock
);
1228 * Lock slab and remove from the partial list.
1230 * Must hold list_lock.
1232 static inline int lock_and_freeze_slab(struct kmem_cache_node
*n
, struct page
*page
)
1234 if (slab_trylock(page
)) {
1235 list_del(&page
->lru
);
1237 SetSlabFrozen(page
);
1244 * Try to allocate a partial slab from a specific node.
1246 static struct page
*get_partial_node(struct kmem_cache_node
*n
)
1251 * Racy check. If we mistakenly see no partial slabs then we
1252 * just allocate an empty slab. If we mistakenly try to get a
1253 * partial slab and there is none available then get_partials()
1256 if (!n
|| !n
->nr_partial
)
1259 spin_lock(&n
->list_lock
);
1260 list_for_each_entry(page
, &n
->partial
, lru
)
1261 if (lock_and_freeze_slab(n
, page
))
1265 spin_unlock(&n
->list_lock
);
1270 * Get a page from somewhere. Search in increasing NUMA distances.
1272 static struct page
*get_any_partial(struct kmem_cache
*s
, gfp_t flags
)
1275 struct zonelist
*zonelist
;
1280 * The defrag ratio allows a configuration of the tradeoffs between
1281 * inter node defragmentation and node local allocations. A lower
1282 * defrag_ratio increases the tendency to do local allocations
1283 * instead of attempting to obtain partial slabs from other nodes.
1285 * If the defrag_ratio is set to 0 then kmalloc() always
1286 * returns node local objects. If the ratio is higher then kmalloc()
1287 * may return off node objects because partial slabs are obtained
1288 * from other nodes and filled up.
1290 * If /sys/slab/xx/defrag_ratio is set to 100 (which makes
1291 * defrag_ratio = 1000) then every (well almost) allocation will
1292 * first attempt to defrag slab caches on other nodes. This means
1293 * scanning over all nodes to look for partial slabs which may be
1294 * expensive if we do it every time we are trying to find a slab
1295 * with available objects.
1297 if (!s
->defrag_ratio
|| get_cycles() % 1024 > s
->defrag_ratio
)
1300 zonelist
= &NODE_DATA(slab_node(current
->mempolicy
))
1301 ->node_zonelists
[gfp_zone(flags
)];
1302 for (z
= zonelist
->zones
; *z
; z
++) {
1303 struct kmem_cache_node
*n
;
1305 n
= get_node(s
, zone_to_nid(*z
));
1307 if (n
&& cpuset_zone_allowed_hardwall(*z
, flags
) &&
1308 n
->nr_partial
> MIN_PARTIAL
) {
1309 page
= get_partial_node(n
);
1319 * Get a partial page, lock it and return it.
1321 static struct page
*get_partial(struct kmem_cache
*s
, gfp_t flags
, int node
)
1324 int searchnode
= (node
== -1) ? numa_node_id() : node
;
1326 page
= get_partial_node(get_node(s
, searchnode
));
1327 if (page
|| (flags
& __GFP_THISNODE
))
1330 return get_any_partial(s
, flags
);
1334 * Move a page back to the lists.
1336 * Must be called with the slab lock held.
1338 * On exit the slab lock will have been dropped.
1340 static void unfreeze_slab(struct kmem_cache
*s
, struct page
*page
)
1342 struct kmem_cache_node
*n
= get_node(s
, page_to_nid(page
));
1344 ClearSlabFrozen(page
);
1348 add_partial(n
, page
);
1349 else if (SlabDebug(page
) && (s
->flags
& SLAB_STORE_USER
))
1354 if (n
->nr_partial
< MIN_PARTIAL
) {
1356 * Adding an empty slab to the partial slabs in order
1357 * to avoid page allocator overhead. This slab needs
1358 * to come after the other slabs with objects in
1359 * order to fill them up. That way the size of the
1360 * partial list stays small. kmem_cache_shrink can
1361 * reclaim empty slabs from the partial list.
1363 add_partial_tail(n
, page
);
1367 discard_slab(s
, page
);
1373 * Remove the cpu slab
1375 static void deactivate_slab(struct kmem_cache
*s
, struct page
*page
, int cpu
)
1378 * Merge cpu freelist into freelist. Typically we get here
1379 * because both freelists are empty. So this is unlikely
1382 while (unlikely(page
->lockless_freelist
)) {
1385 /* Retrieve object from cpu_freelist */
1386 object
= page
->lockless_freelist
;
1387 page
->lockless_freelist
= page
->lockless_freelist
[page
->offset
];
1389 /* And put onto the regular freelist */
1390 object
[page
->offset
] = page
->freelist
;
1391 page
->freelist
= object
;
1394 s
->cpu_slab
[cpu
] = NULL
;
1395 unfreeze_slab(s
, page
);
1398 static void flush_slab(struct kmem_cache
*s
, struct page
*page
, int cpu
)
1401 deactivate_slab(s
, page
, cpu
);
1406 * Called from IPI handler with interrupts disabled.
1408 static void __flush_cpu_slab(struct kmem_cache
*s
, int cpu
)
1410 struct page
*page
= s
->cpu_slab
[cpu
];
1413 flush_slab(s
, page
, cpu
);
1416 static void flush_cpu_slab(void *d
)
1418 struct kmem_cache
*s
= d
;
1419 int cpu
= smp_processor_id();
1421 __flush_cpu_slab(s
, cpu
);
1424 static void flush_all(struct kmem_cache
*s
)
1427 on_each_cpu(flush_cpu_slab
, s
, 1, 1);
1429 unsigned long flags
;
1431 local_irq_save(flags
);
1433 local_irq_restore(flags
);
1438 * Slow path. The lockless freelist is empty or we need to perform
1441 * Interrupts are disabled.
1443 * Processing is still very fast if new objects have been freed to the
1444 * regular freelist. In that case we simply take over the regular freelist
1445 * as the lockless freelist and zap the regular freelist.
1447 * If that is not working then we fall back to the partial lists. We take the
1448 * first element of the freelist as the object to allocate now and move the
1449 * rest of the freelist to the lockless freelist.
1451 * And if we were unable to get a new slab from the partial slab lists then
1452 * we need to allocate a new slab. This is slowest path since we may sleep.
1454 static void *__slab_alloc(struct kmem_cache
*s
,
1455 gfp_t gfpflags
, int node
, void *addr
, struct page
*page
)
1458 int cpu
= smp_processor_id();
1464 if (unlikely(node
!= -1 && page_to_nid(page
) != node
))
1467 object
= page
->freelist
;
1468 if (unlikely(!object
))
1470 if (unlikely(SlabDebug(page
)))
1473 object
= page
->freelist
;
1474 page
->lockless_freelist
= object
[page
->offset
];
1475 page
->inuse
= s
->objects
;
1476 page
->freelist
= NULL
;
1481 deactivate_slab(s
, page
, cpu
);
1484 page
= get_partial(s
, gfpflags
, node
);
1486 s
->cpu_slab
[cpu
] = page
;
1490 page
= new_slab(s
, gfpflags
, node
);
1492 cpu
= smp_processor_id();
1493 if (s
->cpu_slab
[cpu
]) {
1495 * Someone else populated the cpu_slab while we
1496 * enabled interrupts, or we have gotten scheduled
1497 * on another cpu. The page may not be on the
1498 * requested node even if __GFP_THISNODE was
1499 * specified. So we need to recheck.
1502 page_to_nid(s
->cpu_slab
[cpu
]) == node
) {
1504 * Current cpuslab is acceptable and we
1505 * want the current one since its cache hot
1507 discard_slab(s
, page
);
1508 page
= s
->cpu_slab
[cpu
];
1512 /* New slab does not fit our expectations */
1513 flush_slab(s
, s
->cpu_slab
[cpu
], cpu
);
1516 SetSlabFrozen(page
);
1517 s
->cpu_slab
[cpu
] = page
;
1522 object
= page
->freelist
;
1523 if (!alloc_debug_processing(s
, page
, object
, addr
))
1527 page
->freelist
= object
[page
->offset
];
1533 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
1534 * have the fastpath folded into their functions. So no function call
1535 * overhead for requests that can be satisfied on the fastpath.
1537 * The fastpath works by first checking if the lockless freelist can be used.
1538 * If not then __slab_alloc is called for slow processing.
1540 * Otherwise we can simply pick the next object from the lockless free list.
1542 static void __always_inline
*slab_alloc(struct kmem_cache
*s
,
1543 gfp_t gfpflags
, int node
, void *addr
)
1547 unsigned long flags
;
1549 local_irq_save(flags
);
1550 page
= s
->cpu_slab
[smp_processor_id()];
1551 if (unlikely(!page
|| !page
->lockless_freelist
||
1552 (node
!= -1 && page_to_nid(page
) != node
)))
1554 object
= __slab_alloc(s
, gfpflags
, node
, addr
, page
);
1557 object
= page
->lockless_freelist
;
1558 page
->lockless_freelist
= object
[page
->offset
];
1560 local_irq_restore(flags
);
1564 void *kmem_cache_alloc(struct kmem_cache
*s
, gfp_t gfpflags
)
1566 return slab_alloc(s
, gfpflags
, -1, __builtin_return_address(0));
1568 EXPORT_SYMBOL(kmem_cache_alloc
);
1571 void *kmem_cache_alloc_node(struct kmem_cache
*s
, gfp_t gfpflags
, int node
)
1573 return slab_alloc(s
, gfpflags
, node
, __builtin_return_address(0));
1575 EXPORT_SYMBOL(kmem_cache_alloc_node
);
1579 * Slow patch handling. This may still be called frequently since objects
1580 * have a longer lifetime than the cpu slabs in most processing loads.
1582 * So we still attempt to reduce cache line usage. Just take the slab
1583 * lock and free the item. If there is no additional partial page
1584 * handling required then we can return immediately.
1586 static void __slab_free(struct kmem_cache
*s
, struct page
*page
,
1587 void *x
, void *addr
)
1590 void **object
= (void *)x
;
1594 if (unlikely(SlabDebug(page
)))
1597 prior
= object
[page
->offset
] = page
->freelist
;
1598 page
->freelist
= object
;
1601 if (unlikely(SlabFrozen(page
)))
1604 if (unlikely(!page
->inuse
))
1608 * Objects left in the slab. If it
1609 * was not on the partial list before
1612 if (unlikely(!prior
))
1613 add_partial(get_node(s
, page_to_nid(page
)), page
);
1622 * Slab still on the partial list.
1624 remove_partial(s
, page
);
1627 discard_slab(s
, page
);
1631 if (!free_debug_processing(s
, page
, x
, addr
))
1637 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
1638 * can perform fastpath freeing without additional function calls.
1640 * The fastpath is only possible if we are freeing to the current cpu slab
1641 * of this processor. This typically the case if we have just allocated
1644 * If fastpath is not possible then fall back to __slab_free where we deal
1645 * with all sorts of special processing.
1647 static void __always_inline
slab_free(struct kmem_cache
*s
,
1648 struct page
*page
, void *x
, void *addr
)
1650 void **object
= (void *)x
;
1651 unsigned long flags
;
1653 local_irq_save(flags
);
1654 if (likely(page
== s
->cpu_slab
[smp_processor_id()] &&
1655 !SlabDebug(page
))) {
1656 object
[page
->offset
] = page
->lockless_freelist
;
1657 page
->lockless_freelist
= object
;
1659 __slab_free(s
, page
, x
, addr
);
1661 local_irq_restore(flags
);
1664 void kmem_cache_free(struct kmem_cache
*s
, void *x
)
1668 page
= virt_to_head_page(x
);
1670 slab_free(s
, page
, x
, __builtin_return_address(0));
1672 EXPORT_SYMBOL(kmem_cache_free
);
1674 /* Figure out on which slab object the object resides */
1675 static struct page
*get_object_page(const void *x
)
1677 struct page
*page
= virt_to_head_page(x
);
1679 if (!PageSlab(page
))
1686 * Object placement in a slab is made very easy because we always start at
1687 * offset 0. If we tune the size of the object to the alignment then we can
1688 * get the required alignment by putting one properly sized object after
1691 * Notice that the allocation order determines the sizes of the per cpu
1692 * caches. Each processor has always one slab available for allocations.
1693 * Increasing the allocation order reduces the number of times that slabs
1694 * must be moved on and off the partial lists and is therefore a factor in
1699 * Mininum / Maximum order of slab pages. This influences locking overhead
1700 * and slab fragmentation. A higher order reduces the number of partial slabs
1701 * and increases the number of allocations possible without having to
1702 * take the list_lock.
1704 static int slub_min_order
;
1705 static int slub_max_order
= DEFAULT_MAX_ORDER
;
1706 static int slub_min_objects
= DEFAULT_MIN_OBJECTS
;
1709 * Merge control. If this is set then no merging of slab caches will occur.
1710 * (Could be removed. This was introduced to pacify the merge skeptics.)
1712 static int slub_nomerge
;
1715 * Calculate the order of allocation given an slab object size.
1717 * The order of allocation has significant impact on performance and other
1718 * system components. Generally order 0 allocations should be preferred since
1719 * order 0 does not cause fragmentation in the page allocator. Larger objects
1720 * be problematic to put into order 0 slabs because there may be too much
1721 * unused space left. We go to a higher order if more than 1/8th of the slab
1724 * In order to reach satisfactory performance we must ensure that a minimum
1725 * number of objects is in one slab. Otherwise we may generate too much
1726 * activity on the partial lists which requires taking the list_lock. This is
1727 * less a concern for large slabs though which are rarely used.
1729 * slub_max_order specifies the order where we begin to stop considering the
1730 * number of objects in a slab as critical. If we reach slub_max_order then
1731 * we try to keep the page order as low as possible. So we accept more waste
1732 * of space in favor of a small page order.
1734 * Higher order allocations also allow the placement of more objects in a
1735 * slab and thereby reduce object handling overhead. If the user has
1736 * requested a higher mininum order then we start with that one instead of
1737 * the smallest order which will fit the object.
1739 static inline int slab_order(int size
, int min_objects
,
1740 int max_order
, int fract_leftover
)
1744 int min_order
= slub_min_order
;
1747 * If we would create too many object per slab then reduce
1748 * the slab order even if it goes below slub_min_order.
1750 while (min_order
> 0 &&
1751 (PAGE_SIZE
<< min_order
) >= MAX_OBJECTS_PER_SLAB
* size
)
1754 for (order
= max(min_order
,
1755 fls(min_objects
* size
- 1) - PAGE_SHIFT
);
1756 order
<= max_order
; order
++) {
1758 unsigned long slab_size
= PAGE_SIZE
<< order
;
1760 if (slab_size
< min_objects
* size
)
1763 rem
= slab_size
% size
;
1765 if (rem
<= slab_size
/ fract_leftover
)
1768 /* If the next size is too high then exit now */
1769 if (slab_size
* 2 >= MAX_OBJECTS_PER_SLAB
* size
)
1776 static inline int calculate_order(int size
)
1783 * Attempt to find best configuration for a slab. This
1784 * works by first attempting to generate a layout with
1785 * the best configuration and backing off gradually.
1787 * First we reduce the acceptable waste in a slab. Then
1788 * we reduce the minimum objects required in a slab.
1790 min_objects
= slub_min_objects
;
1791 while (min_objects
> 1) {
1793 while (fraction
>= 4) {
1794 order
= slab_order(size
, min_objects
,
1795 slub_max_order
, fraction
);
1796 if (order
<= slub_max_order
)
1804 * We were unable to place multiple objects in a slab. Now
1805 * lets see if we can place a single object there.
1807 order
= slab_order(size
, 1, slub_max_order
, 1);
1808 if (order
<= slub_max_order
)
1812 * Doh this slab cannot be placed using slub_max_order.
1814 order
= slab_order(size
, 1, MAX_ORDER
, 1);
1815 if (order
<= MAX_ORDER
)
1821 * Figure out what the alignment of the objects will be.
1823 static unsigned long calculate_alignment(unsigned long flags
,
1824 unsigned long align
, unsigned long size
)
1827 * If the user wants hardware cache aligned objects then
1828 * follow that suggestion if the object is sufficiently
1831 * The hardware cache alignment cannot override the
1832 * specified alignment though. If that is greater
1835 if ((flags
& SLAB_HWCACHE_ALIGN
) &&
1836 size
> cache_line_size() / 2)
1837 return max_t(unsigned long, align
, cache_line_size());
1839 if (align
< ARCH_SLAB_MINALIGN
)
1840 return ARCH_SLAB_MINALIGN
;
1842 return ALIGN(align
, sizeof(void *));
1845 static void init_kmem_cache_node(struct kmem_cache_node
*n
)
1848 atomic_long_set(&n
->nr_slabs
, 0);
1849 spin_lock_init(&n
->list_lock
);
1850 INIT_LIST_HEAD(&n
->partial
);
1851 INIT_LIST_HEAD(&n
->full
);
1856 * No kmalloc_node yet so do it by hand. We know that this is the first
1857 * slab on the node for this slabcache. There are no concurrent accesses
1860 * Note that this function only works on the kmalloc_node_cache
1861 * when allocating for the kmalloc_node_cache.
1863 static struct kmem_cache_node
* __init
early_kmem_cache_node_alloc(gfp_t gfpflags
,
1867 struct kmem_cache_node
*n
;
1869 BUG_ON(kmalloc_caches
->size
< sizeof(struct kmem_cache_node
));
1871 page
= new_slab(kmalloc_caches
, gfpflags
| GFP_THISNODE
, node
);
1876 page
->freelist
= get_freepointer(kmalloc_caches
, n
);
1878 kmalloc_caches
->node
[node
] = n
;
1879 init_object(kmalloc_caches
, n
, 1);
1880 init_tracking(kmalloc_caches
, n
);
1881 init_kmem_cache_node(n
);
1882 atomic_long_inc(&n
->nr_slabs
);
1883 add_partial(n
, page
);
1886 * new_slab() disables interupts. If we do not reenable interrupts here
1887 * then bootup would continue with interrupts disabled.
1893 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
1897 for_each_online_node(node
) {
1898 struct kmem_cache_node
*n
= s
->node
[node
];
1899 if (n
&& n
!= &s
->local_node
)
1900 kmem_cache_free(kmalloc_caches
, n
);
1901 s
->node
[node
] = NULL
;
1905 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
1910 if (slab_state
>= UP
)
1911 local_node
= page_to_nid(virt_to_page(s
));
1915 for_each_online_node(node
) {
1916 struct kmem_cache_node
*n
;
1918 if (local_node
== node
)
1921 if (slab_state
== DOWN
) {
1922 n
= early_kmem_cache_node_alloc(gfpflags
,
1926 n
= kmem_cache_alloc_node(kmalloc_caches
,
1930 free_kmem_cache_nodes(s
);
1936 init_kmem_cache_node(n
);
1941 static void free_kmem_cache_nodes(struct kmem_cache
*s
)
1945 static int init_kmem_cache_nodes(struct kmem_cache
*s
, gfp_t gfpflags
)
1947 init_kmem_cache_node(&s
->local_node
);
1953 * calculate_sizes() determines the order and the distribution of data within
1956 static int calculate_sizes(struct kmem_cache
*s
)
1958 unsigned long flags
= s
->flags
;
1959 unsigned long size
= s
->objsize
;
1960 unsigned long align
= s
->align
;
1963 * Determine if we can poison the object itself. If the user of
1964 * the slab may touch the object after free or before allocation
1965 * then we should never poison the object itself.
1967 if ((flags
& SLAB_POISON
) && !(flags
& SLAB_DESTROY_BY_RCU
) &&
1969 s
->flags
|= __OBJECT_POISON
;
1971 s
->flags
&= ~__OBJECT_POISON
;
1974 * Round up object size to the next word boundary. We can only
1975 * place the free pointer at word boundaries and this determines
1976 * the possible location of the free pointer.
1978 size
= ALIGN(size
, sizeof(void *));
1980 #ifdef CONFIG_SLUB_DEBUG
1982 * If we are Redzoning then check if there is some space between the
1983 * end of the object and the free pointer. If not then add an
1984 * additional word to have some bytes to store Redzone information.
1986 if ((flags
& SLAB_RED_ZONE
) && size
== s
->objsize
)
1987 size
+= sizeof(void *);
1991 * With that we have determined the number of bytes in actual use
1992 * by the object. This is the potential offset to the free pointer.
1996 if (((flags
& (SLAB_DESTROY_BY_RCU
| SLAB_POISON
)) ||
1999 * Relocate free pointer after the object if it is not
2000 * permitted to overwrite the first word of the object on
2003 * This is the case if we do RCU, have a constructor or
2004 * destructor or are poisoning the objects.
2007 size
+= sizeof(void *);
2010 #ifdef CONFIG_SLUB_DEBUG
2011 if (flags
& SLAB_STORE_USER
)
2013 * Need to store information about allocs and frees after
2016 size
+= 2 * sizeof(struct track
);
2018 if (flags
& SLAB_RED_ZONE
)
2020 * Add some empty padding so that we can catch
2021 * overwrites from earlier objects rather than let
2022 * tracking information or the free pointer be
2023 * corrupted if an user writes before the start
2026 size
+= sizeof(void *);
2030 * Determine the alignment based on various parameters that the
2031 * user specified and the dynamic determination of cache line size
2034 align
= calculate_alignment(flags
, align
, s
->objsize
);
2037 * SLUB stores one object immediately after another beginning from
2038 * offset 0. In order to align the objects we have to simply size
2039 * each object to conform to the alignment.
2041 size
= ALIGN(size
, align
);
2044 s
->order
= calculate_order(size
);
2049 * Determine the number of objects per slab
2051 s
->objects
= (PAGE_SIZE
<< s
->order
) / size
;
2054 * Verify that the number of objects is within permitted limits.
2055 * The page->inuse field is only 16 bit wide! So we cannot have
2056 * more than 64k objects per slab.
2058 if (!s
->objects
|| s
->objects
> MAX_OBJECTS_PER_SLAB
)
2064 static int kmem_cache_open(struct kmem_cache
*s
, gfp_t gfpflags
,
2065 const char *name
, size_t size
,
2066 size_t align
, unsigned long flags
,
2067 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
2069 memset(s
, 0, kmem_size
);
2075 kmem_cache_open_debug_check(s
);
2077 if (!calculate_sizes(s
))
2082 s
->defrag_ratio
= 100;
2085 if (init_kmem_cache_nodes(s
, gfpflags
& ~SLUB_DMA
))
2088 if (flags
& SLAB_PANIC
)
2089 panic("Cannot create slab %s size=%lu realsize=%u "
2090 "order=%u offset=%u flags=%lx\n",
2091 s
->name
, (unsigned long)size
, s
->size
, s
->order
,
2097 * Check if a given pointer is valid
2099 int kmem_ptr_validate(struct kmem_cache
*s
, const void *object
)
2103 page
= get_object_page(object
);
2105 if (!page
|| s
!= page
->slab
)
2106 /* No slab or wrong slab */
2109 if (!check_valid_pointer(s
, page
, object
))
2113 * We could also check if the object is on the slabs freelist.
2114 * But this would be too expensive and it seems that the main
2115 * purpose of kmem_ptr_valid is to check if the object belongs
2116 * to a certain slab.
2120 EXPORT_SYMBOL(kmem_ptr_validate
);
2123 * Determine the size of a slab object
2125 unsigned int kmem_cache_size(struct kmem_cache
*s
)
2129 EXPORT_SYMBOL(kmem_cache_size
);
2131 const char *kmem_cache_name(struct kmem_cache
*s
)
2135 EXPORT_SYMBOL(kmem_cache_name
);
2138 * Attempt to free all slabs on a node. Return the number of slabs we
2139 * were unable to free.
2141 static int free_list(struct kmem_cache
*s
, struct kmem_cache_node
*n
,
2142 struct list_head
*list
)
2144 int slabs_inuse
= 0;
2145 unsigned long flags
;
2146 struct page
*page
, *h
;
2148 spin_lock_irqsave(&n
->list_lock
, flags
);
2149 list_for_each_entry_safe(page
, h
, list
, lru
)
2151 list_del(&page
->lru
);
2152 discard_slab(s
, page
);
2155 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2160 * Release all resources used by a slab cache.
2162 static int kmem_cache_close(struct kmem_cache
*s
)
2168 /* Attempt to free all objects */
2169 for_each_online_node(node
) {
2170 struct kmem_cache_node
*n
= get_node(s
, node
);
2172 n
->nr_partial
-= free_list(s
, n
, &n
->partial
);
2173 if (atomic_long_read(&n
->nr_slabs
))
2176 free_kmem_cache_nodes(s
);
2181 * Close a cache and release the kmem_cache structure
2182 * (must be used for caches created using kmem_cache_create)
2184 void kmem_cache_destroy(struct kmem_cache
*s
)
2186 down_write(&slub_lock
);
2190 if (kmem_cache_close(s
))
2192 sysfs_slab_remove(s
);
2195 up_write(&slub_lock
);
2197 EXPORT_SYMBOL(kmem_cache_destroy
);
2199 /********************************************************************
2201 *******************************************************************/
2203 struct kmem_cache kmalloc_caches
[KMALLOC_SHIFT_HIGH
+ 1] __cacheline_aligned
;
2204 EXPORT_SYMBOL(kmalloc_caches
);
2206 #ifdef CONFIG_ZONE_DMA
2207 static struct kmem_cache
*kmalloc_caches_dma
[KMALLOC_SHIFT_HIGH
+ 1];
2210 static int __init
setup_slub_min_order(char *str
)
2212 get_option (&str
, &slub_min_order
);
2217 __setup("slub_min_order=", setup_slub_min_order
);
2219 static int __init
setup_slub_max_order(char *str
)
2221 get_option (&str
, &slub_max_order
);
2226 __setup("slub_max_order=", setup_slub_max_order
);
2228 static int __init
setup_slub_min_objects(char *str
)
2230 get_option (&str
, &slub_min_objects
);
2235 __setup("slub_min_objects=", setup_slub_min_objects
);
2237 static int __init
setup_slub_nomerge(char *str
)
2243 __setup("slub_nomerge", setup_slub_nomerge
);
2245 static struct kmem_cache
*create_kmalloc_cache(struct kmem_cache
*s
,
2246 const char *name
, int size
, gfp_t gfp_flags
)
2248 unsigned int flags
= 0;
2250 if (gfp_flags
& SLUB_DMA
)
2251 flags
= SLAB_CACHE_DMA
;
2253 down_write(&slub_lock
);
2254 if (!kmem_cache_open(s
, gfp_flags
, name
, size
, ARCH_KMALLOC_MINALIGN
,
2258 list_add(&s
->list
, &slab_caches
);
2259 up_write(&slub_lock
);
2260 if (sysfs_slab_add(s
))
2265 panic("Creation of kmalloc slab %s size=%d failed.\n", name
, size
);
2268 static struct kmem_cache
*get_slab(size_t size
, gfp_t flags
)
2270 int index
= kmalloc_index(size
);
2275 /* Allocation too large? */
2278 #ifdef CONFIG_ZONE_DMA
2279 if ((flags
& SLUB_DMA
)) {
2280 struct kmem_cache
*s
;
2281 struct kmem_cache
*x
;
2285 s
= kmalloc_caches_dma
[index
];
2289 /* Dynamically create dma cache */
2290 x
= kmalloc(kmem_size
, flags
& ~SLUB_DMA
);
2292 panic("Unable to allocate memory for dma cache\n");
2294 if (index
<= KMALLOC_SHIFT_HIGH
)
2295 realsize
= 1 << index
;
2303 text
= kasprintf(flags
& ~SLUB_DMA
, "kmalloc_dma-%d",
2304 (unsigned int)realsize
);
2305 s
= create_kmalloc_cache(x
, text
, realsize
, flags
);
2306 kmalloc_caches_dma
[index
] = s
;
2310 return &kmalloc_caches
[index
];
2313 void *__kmalloc(size_t size
, gfp_t flags
)
2315 struct kmem_cache
*s
= get_slab(size
, flags
);
2318 return slab_alloc(s
, flags
, -1, __builtin_return_address(0));
2319 return ZERO_SIZE_PTR
;
2321 EXPORT_SYMBOL(__kmalloc
);
2324 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
2326 struct kmem_cache
*s
= get_slab(size
, flags
);
2329 return slab_alloc(s
, flags
, node
, __builtin_return_address(0));
2330 return ZERO_SIZE_PTR
;
2332 EXPORT_SYMBOL(__kmalloc_node
);
2335 size_t ksize(const void *object
)
2338 struct kmem_cache
*s
;
2340 if (object
== ZERO_SIZE_PTR
)
2343 page
= get_object_page(object
);
2349 * Debugging requires use of the padding between object
2350 * and whatever may come after it.
2352 if (s
->flags
& (SLAB_RED_ZONE
| SLAB_POISON
))
2356 * If we have the need to store the freelist pointer
2357 * back there or track user information then we can
2358 * only use the space before that information.
2360 if (s
->flags
& (SLAB_DESTROY_BY_RCU
| SLAB_STORE_USER
))
2364 * Else we can use all the padding etc for the allocation
2368 EXPORT_SYMBOL(ksize
);
2370 void kfree(const void *x
)
2372 struct kmem_cache
*s
;
2376 * This has to be an unsigned comparison. According to Linus
2377 * some gcc version treat a pointer as a signed entity. Then
2378 * this comparison would be true for all "negative" pointers
2379 * (which would cover the whole upper half of the address space).
2381 if ((unsigned long)x
<= (unsigned long)ZERO_SIZE_PTR
)
2384 page
= virt_to_head_page(x
);
2387 slab_free(s
, page
, (void *)x
, __builtin_return_address(0));
2389 EXPORT_SYMBOL(kfree
);
2392 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
2393 * the remaining slabs by the number of items in use. The slabs with the
2394 * most items in use come first. New allocations will then fill those up
2395 * and thus they can be removed from the partial lists.
2397 * The slabs with the least items are placed last. This results in them
2398 * being allocated from last increasing the chance that the last objects
2399 * are freed in them.
2401 int kmem_cache_shrink(struct kmem_cache
*s
)
2405 struct kmem_cache_node
*n
;
2408 struct list_head
*slabs_by_inuse
=
2409 kmalloc(sizeof(struct list_head
) * s
->objects
, GFP_KERNEL
);
2410 unsigned long flags
;
2412 if (!slabs_by_inuse
)
2416 for_each_online_node(node
) {
2417 n
= get_node(s
, node
);
2422 for (i
= 0; i
< s
->objects
; i
++)
2423 INIT_LIST_HEAD(slabs_by_inuse
+ i
);
2425 spin_lock_irqsave(&n
->list_lock
, flags
);
2428 * Build lists indexed by the items in use in each slab.
2430 * Note that concurrent frees may occur while we hold the
2431 * list_lock. page->inuse here is the upper limit.
2433 list_for_each_entry_safe(page
, t
, &n
->partial
, lru
) {
2434 if (!page
->inuse
&& slab_trylock(page
)) {
2436 * Must hold slab lock here because slab_free
2437 * may have freed the last object and be
2438 * waiting to release the slab.
2440 list_del(&page
->lru
);
2443 discard_slab(s
, page
);
2445 if (n
->nr_partial
> MAX_PARTIAL
)
2446 list_move(&page
->lru
,
2447 slabs_by_inuse
+ page
->inuse
);
2451 if (n
->nr_partial
<= MAX_PARTIAL
)
2455 * Rebuild the partial list with the slabs filled up most
2456 * first and the least used slabs at the end.
2458 for (i
= s
->objects
- 1; i
>= 0; i
--)
2459 list_splice(slabs_by_inuse
+ i
, n
->partial
.prev
);
2462 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2465 kfree(slabs_by_inuse
);
2468 EXPORT_SYMBOL(kmem_cache_shrink
);
2471 * krealloc - reallocate memory. The contents will remain unchanged.
2472 * @p: object to reallocate memory for.
2473 * @new_size: how many bytes of memory are required.
2474 * @flags: the type of memory to allocate.
2476 * The contents of the object pointed to are preserved up to the
2477 * lesser of the new and old sizes. If @p is %NULL, krealloc()
2478 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
2479 * %NULL pointer, the object pointed to is freed.
2481 void *krealloc(const void *p
, size_t new_size
, gfp_t flags
)
2486 if (unlikely(!p
|| p
== ZERO_SIZE_PTR
))
2487 return kmalloc(new_size
, flags
);
2489 if (unlikely(!new_size
)) {
2491 return ZERO_SIZE_PTR
;
2498 ret
= kmalloc(new_size
, flags
);
2500 memcpy(ret
, p
, min(new_size
, ks
));
2505 EXPORT_SYMBOL(krealloc
);
2507 /********************************************************************
2508 * Basic setup of slabs
2509 *******************************************************************/
2511 void __init
kmem_cache_init(void)
2518 * Must first have the slab cache available for the allocations of the
2519 * struct kmem_cache_node's. There is special bootstrap code in
2520 * kmem_cache_open for slab_state == DOWN.
2522 create_kmalloc_cache(&kmalloc_caches
[0], "kmem_cache_node",
2523 sizeof(struct kmem_cache_node
), GFP_KERNEL
);
2524 kmalloc_caches
[0].refcount
= -1;
2528 /* Able to allocate the per node structures */
2529 slab_state
= PARTIAL
;
2531 /* Caches that are not of the two-to-the-power-of size */
2532 if (KMALLOC_MIN_SIZE
<= 64) {
2533 create_kmalloc_cache(&kmalloc_caches
[1],
2534 "kmalloc-96", 96, GFP_KERNEL
);
2537 if (KMALLOC_MIN_SIZE
<= 128) {
2538 create_kmalloc_cache(&kmalloc_caches
[2],
2539 "kmalloc-192", 192, GFP_KERNEL
);
2543 for (i
= KMALLOC_SHIFT_LOW
; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
2544 create_kmalloc_cache(&kmalloc_caches
[i
],
2545 "kmalloc", 1 << i
, GFP_KERNEL
);
2551 /* Provide the correct kmalloc names now that the caches are up */
2552 for (i
= KMALLOC_SHIFT_LOW
; i
<= KMALLOC_SHIFT_HIGH
; i
++)
2553 kmalloc_caches
[i
]. name
=
2554 kasprintf(GFP_KERNEL
, "kmalloc-%d", 1 << i
);
2557 register_cpu_notifier(&slab_notifier
);
2560 kmem_size
= offsetof(struct kmem_cache
, cpu_slab
) +
2561 nr_cpu_ids
* sizeof(struct page
*);
2563 printk(KERN_INFO
"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
2564 " CPUs=%d, Nodes=%d\n",
2565 caches
, cache_line_size(),
2566 slub_min_order
, slub_max_order
, slub_min_objects
,
2567 nr_cpu_ids
, nr_node_ids
);
2571 * Find a mergeable slab cache
2573 static int slab_unmergeable(struct kmem_cache
*s
)
2575 if (slub_nomerge
|| (s
->flags
& SLUB_NEVER_MERGE
))
2582 * We may have set a slab to be unmergeable during bootstrap.
2584 if (s
->refcount
< 0)
2590 static struct kmem_cache
*find_mergeable(size_t size
,
2591 size_t align
, unsigned long flags
,
2592 void (*ctor
)(void *, struct kmem_cache
*, unsigned long))
2594 struct kmem_cache
*s
;
2596 if (slub_nomerge
|| (flags
& SLUB_NEVER_MERGE
))
2602 size
= ALIGN(size
, sizeof(void *));
2603 align
= calculate_alignment(flags
, align
, size
);
2604 size
= ALIGN(size
, align
);
2606 list_for_each_entry(s
, &slab_caches
, list
) {
2607 if (slab_unmergeable(s
))
2613 if (((flags
| slub_debug
) & SLUB_MERGE_SAME
) !=
2614 (s
->flags
& SLUB_MERGE_SAME
))
2617 * Check if alignment is compatible.
2618 * Courtesy of Adrian Drzewiecki
2620 if ((s
->size
& ~(align
-1)) != s
->size
)
2623 if (s
->size
- size
>= sizeof(void *))
2631 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
,
2632 size_t align
, unsigned long flags
,
2633 void (*ctor
)(void *, struct kmem_cache
*, unsigned long),
2634 void (*dtor
)(void *, struct kmem_cache
*, unsigned long))
2636 struct kmem_cache
*s
;
2639 down_write(&slub_lock
);
2640 s
= find_mergeable(size
, align
, flags
, ctor
);
2644 * Adjust the object sizes so that we clear
2645 * the complete object on kzalloc.
2647 s
->objsize
= max(s
->objsize
, (int)size
);
2648 s
->inuse
= max_t(int, s
->inuse
, ALIGN(size
, sizeof(void *)));
2649 if (sysfs_slab_alias(s
, name
))
2652 s
= kmalloc(kmem_size
, GFP_KERNEL
);
2653 if (s
&& kmem_cache_open(s
, GFP_KERNEL
, name
,
2654 size
, align
, flags
, ctor
)) {
2655 if (sysfs_slab_add(s
)) {
2659 list_add(&s
->list
, &slab_caches
);
2663 up_write(&slub_lock
);
2667 up_write(&slub_lock
);
2668 if (flags
& SLAB_PANIC
)
2669 panic("Cannot create slabcache %s\n", name
);
2674 EXPORT_SYMBOL(kmem_cache_create
);
2676 void *kmem_cache_zalloc(struct kmem_cache
*s
, gfp_t flags
)
2680 x
= slab_alloc(s
, flags
, -1, __builtin_return_address(0));
2682 memset(x
, 0, s
->objsize
);
2685 EXPORT_SYMBOL(kmem_cache_zalloc
);
2689 * Use the cpu notifier to insure that the cpu slabs are flushed when
2692 static int __cpuinit
slab_cpuup_callback(struct notifier_block
*nfb
,
2693 unsigned long action
, void *hcpu
)
2695 long cpu
= (long)hcpu
;
2696 struct kmem_cache
*s
;
2697 unsigned long flags
;
2700 case CPU_UP_CANCELED
:
2701 case CPU_UP_CANCELED_FROZEN
:
2703 case CPU_DEAD_FROZEN
:
2704 down_read(&slub_lock
);
2705 list_for_each_entry(s
, &slab_caches
, list
) {
2706 local_irq_save(flags
);
2707 __flush_cpu_slab(s
, cpu
);
2708 local_irq_restore(flags
);
2710 up_read(&slub_lock
);
2718 static struct notifier_block __cpuinitdata slab_notifier
=
2719 { &slab_cpuup_callback
, NULL
, 0 };
2723 void *__kmalloc_track_caller(size_t size
, gfp_t gfpflags
, void *caller
)
2725 struct kmem_cache
*s
= get_slab(size
, gfpflags
);
2728 return ZERO_SIZE_PTR
;
2730 return slab_alloc(s
, gfpflags
, -1, caller
);
2733 void *__kmalloc_node_track_caller(size_t size
, gfp_t gfpflags
,
2734 int node
, void *caller
)
2736 struct kmem_cache
*s
= get_slab(size
, gfpflags
);
2739 return ZERO_SIZE_PTR
;
2741 return slab_alloc(s
, gfpflags
, node
, caller
);
2744 #if defined(CONFIG_SYSFS) && defined(CONFIG_SLUB_DEBUG)
2745 static int validate_slab(struct kmem_cache
*s
, struct page
*page
)
2748 void *addr
= page_address(page
);
2749 DECLARE_BITMAP(map
, s
->objects
);
2751 if (!check_slab(s
, page
) ||
2752 !on_freelist(s
, page
, NULL
))
2755 /* Now we know that a valid freelist exists */
2756 bitmap_zero(map
, s
->objects
);
2758 for_each_free_object(p
, s
, page
->freelist
) {
2759 set_bit(slab_index(p
, s
, addr
), map
);
2760 if (!check_object(s
, page
, p
, 0))
2764 for_each_object(p
, s
, addr
)
2765 if (!test_bit(slab_index(p
, s
, addr
), map
))
2766 if (!check_object(s
, page
, p
, 1))
2771 static void validate_slab_slab(struct kmem_cache
*s
, struct page
*page
)
2773 if (slab_trylock(page
)) {
2774 validate_slab(s
, page
);
2777 printk(KERN_INFO
"SLUB %s: Skipped busy slab 0x%p\n",
2780 if (s
->flags
& DEBUG_DEFAULT_FLAGS
) {
2781 if (!SlabDebug(page
))
2782 printk(KERN_ERR
"SLUB %s: SlabDebug not set "
2783 "on slab 0x%p\n", s
->name
, page
);
2785 if (SlabDebug(page
))
2786 printk(KERN_ERR
"SLUB %s: SlabDebug set on "
2787 "slab 0x%p\n", s
->name
, page
);
2791 static int validate_slab_node(struct kmem_cache
*s
, struct kmem_cache_node
*n
)
2793 unsigned long count
= 0;
2795 unsigned long flags
;
2797 spin_lock_irqsave(&n
->list_lock
, flags
);
2799 list_for_each_entry(page
, &n
->partial
, lru
) {
2800 validate_slab_slab(s
, page
);
2803 if (count
!= n
->nr_partial
)
2804 printk(KERN_ERR
"SLUB %s: %ld partial slabs counted but "
2805 "counter=%ld\n", s
->name
, count
, n
->nr_partial
);
2807 if (!(s
->flags
& SLAB_STORE_USER
))
2810 list_for_each_entry(page
, &n
->full
, lru
) {
2811 validate_slab_slab(s
, page
);
2814 if (count
!= atomic_long_read(&n
->nr_slabs
))
2815 printk(KERN_ERR
"SLUB: %s %ld slabs counted but "
2816 "counter=%ld\n", s
->name
, count
,
2817 atomic_long_read(&n
->nr_slabs
));
2820 spin_unlock_irqrestore(&n
->list_lock
, flags
);
2824 static unsigned long validate_slab_cache(struct kmem_cache
*s
)
2827 unsigned long count
= 0;
2830 for_each_online_node(node
) {
2831 struct kmem_cache_node
*n
= get_node(s
, node
);
2833 count
+= validate_slab_node(s
, n
);
2838 #ifdef SLUB_RESILIENCY_TEST
2839 static void resiliency_test(void)
2843 printk(KERN_ERR
"SLUB resiliency testing\n");
2844 printk(KERN_ERR
"-----------------------\n");
2845 printk(KERN_ERR
"A. Corruption after allocation\n");
2847 p
= kzalloc(16, GFP_KERNEL
);
2849 printk(KERN_ERR
"\n1. kmalloc-16: Clobber Redzone/next pointer"
2850 " 0x12->0x%p\n\n", p
+ 16);
2852 validate_slab_cache(kmalloc_caches
+ 4);
2854 /* Hmmm... The next two are dangerous */
2855 p
= kzalloc(32, GFP_KERNEL
);
2856 p
[32 + sizeof(void *)] = 0x34;
2857 printk(KERN_ERR
"\n2. kmalloc-32: Clobber next pointer/next slab"
2858 " 0x34 -> -0x%p\n", p
);
2859 printk(KERN_ERR
"If allocated object is overwritten then not detectable\n\n");
2861 validate_slab_cache(kmalloc_caches
+ 5);
2862 p
= kzalloc(64, GFP_KERNEL
);
2863 p
+= 64 + (get_cycles() & 0xff) * sizeof(void *);
2865 printk(KERN_ERR
"\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
2867 printk(KERN_ERR
"If allocated object is overwritten then not detectable\n\n");
2868 validate_slab_cache(kmalloc_caches
+ 6);
2870 printk(KERN_ERR
"\nB. Corruption after free\n");
2871 p
= kzalloc(128, GFP_KERNEL
);
2874 printk(KERN_ERR
"1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p
);
2875 validate_slab_cache(kmalloc_caches
+ 7);
2877 p
= kzalloc(256, GFP_KERNEL
);
2880 printk(KERN_ERR
"\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p
);
2881 validate_slab_cache(kmalloc_caches
+ 8);
2883 p
= kzalloc(512, GFP_KERNEL
);
2886 printk(KERN_ERR
"\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p
);
2887 validate_slab_cache(kmalloc_caches
+ 9);
2890 static void resiliency_test(void) {};
2894 * Generate lists of code addresses where slabcache objects are allocated
2899 unsigned long count
;
2912 unsigned long count
;
2913 struct location
*loc
;
2916 static void free_loc_track(struct loc_track
*t
)
2919 free_pages((unsigned long)t
->loc
,
2920 get_order(sizeof(struct location
) * t
->max
));
2923 static int alloc_loc_track(struct loc_track
*t
, unsigned long max
, gfp_t flags
)
2928 order
= get_order(sizeof(struct location
) * max
);
2930 l
= (void *)__get_free_pages(flags
, order
);
2935 memcpy(l
, t
->loc
, sizeof(struct location
) * t
->count
);
2943 static int add_location(struct loc_track
*t
, struct kmem_cache
*s
,
2944 const struct track
*track
)
2946 long start
, end
, pos
;
2949 unsigned long age
= jiffies
- track
->when
;
2955 pos
= start
+ (end
- start
+ 1) / 2;
2958 * There is nothing at "end". If we end up there
2959 * we need to add something to before end.
2964 caddr
= t
->loc
[pos
].addr
;
2965 if (track
->addr
== caddr
) {
2971 if (age
< l
->min_time
)
2973 if (age
> l
->max_time
)
2976 if (track
->pid
< l
->min_pid
)
2977 l
->min_pid
= track
->pid
;
2978 if (track
->pid
> l
->max_pid
)
2979 l
->max_pid
= track
->pid
;
2981 cpu_set(track
->cpu
, l
->cpus
);
2983 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
2987 if (track
->addr
< caddr
)
2994 * Not found. Insert new tracking element.
2996 if (t
->count
>= t
->max
&& !alloc_loc_track(t
, 2 * t
->max
, GFP_ATOMIC
))
3002 (t
->count
- pos
) * sizeof(struct location
));
3005 l
->addr
= track
->addr
;
3009 l
->min_pid
= track
->pid
;
3010 l
->max_pid
= track
->pid
;
3011 cpus_clear(l
->cpus
);
3012 cpu_set(track
->cpu
, l
->cpus
);
3013 nodes_clear(l
->nodes
);
3014 node_set(page_to_nid(virt_to_page(track
)), l
->nodes
);
3018 static void process_slab(struct loc_track
*t
, struct kmem_cache
*s
,
3019 struct page
*page
, enum track_item alloc
)
3021 void *addr
= page_address(page
);
3022 DECLARE_BITMAP(map
, s
->objects
);
3025 bitmap_zero(map
, s
->objects
);
3026 for_each_free_object(p
, s
, page
->freelist
)
3027 set_bit(slab_index(p
, s
, addr
), map
);
3029 for_each_object(p
, s
, addr
)
3030 if (!test_bit(slab_index(p
, s
, addr
), map
))
3031 add_location(t
, s
, get_track(s
, p
, alloc
));
3034 static int list_locations(struct kmem_cache
*s
, char *buf
,
3035 enum track_item alloc
)
3039 struct loc_track t
= { 0, 0, NULL
};
3042 if (!alloc_loc_track(&t
, PAGE_SIZE
/ sizeof(struct location
),
3044 return sprintf(buf
, "Out of memory\n");
3046 /* Push back cpu slabs */
3049 for_each_online_node(node
) {
3050 struct kmem_cache_node
*n
= get_node(s
, node
);
3051 unsigned long flags
;
3054 if (!atomic_read(&n
->nr_slabs
))
3057 spin_lock_irqsave(&n
->list_lock
, flags
);
3058 list_for_each_entry(page
, &n
->partial
, lru
)
3059 process_slab(&t
, s
, page
, alloc
);
3060 list_for_each_entry(page
, &n
->full
, lru
)
3061 process_slab(&t
, s
, page
, alloc
);
3062 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3065 for (i
= 0; i
< t
.count
; i
++) {
3066 struct location
*l
= &t
.loc
[i
];
3068 if (n
> PAGE_SIZE
- 100)
3070 n
+= sprintf(buf
+ n
, "%7ld ", l
->count
);
3073 n
+= sprint_symbol(buf
+ n
, (unsigned long)l
->addr
);
3075 n
+= sprintf(buf
+ n
, "<not-available>");
3077 if (l
->sum_time
!= l
->min_time
) {
3078 unsigned long remainder
;
3080 n
+= sprintf(buf
+ n
, " age=%ld/%ld/%ld",
3082 div_long_long_rem(l
->sum_time
, l
->count
, &remainder
),
3085 n
+= sprintf(buf
+ n
, " age=%ld",
3088 if (l
->min_pid
!= l
->max_pid
)
3089 n
+= sprintf(buf
+ n
, " pid=%ld-%ld",
3090 l
->min_pid
, l
->max_pid
);
3092 n
+= sprintf(buf
+ n
, " pid=%ld",
3095 if (num_online_cpus() > 1 && !cpus_empty(l
->cpus
) &&
3096 n
< PAGE_SIZE
- 60) {
3097 n
+= sprintf(buf
+ n
, " cpus=");
3098 n
+= cpulist_scnprintf(buf
+ n
, PAGE_SIZE
- n
- 50,
3102 if (num_online_nodes() > 1 && !nodes_empty(l
->nodes
) &&
3103 n
< PAGE_SIZE
- 60) {
3104 n
+= sprintf(buf
+ n
, " nodes=");
3105 n
+= nodelist_scnprintf(buf
+ n
, PAGE_SIZE
- n
- 50,
3109 n
+= sprintf(buf
+ n
, "\n");
3114 n
+= sprintf(buf
, "No data\n");
3118 static unsigned long count_partial(struct kmem_cache_node
*n
)
3120 unsigned long flags
;
3121 unsigned long x
= 0;
3124 spin_lock_irqsave(&n
->list_lock
, flags
);
3125 list_for_each_entry(page
, &n
->partial
, lru
)
3127 spin_unlock_irqrestore(&n
->list_lock
, flags
);
3131 enum slab_stat_type
{
3138 #define SO_FULL (1 << SL_FULL)
3139 #define SO_PARTIAL (1 << SL_PARTIAL)
3140 #define SO_CPU (1 << SL_CPU)
3141 #define SO_OBJECTS (1 << SL_OBJECTS)
3143 static unsigned long slab_objects(struct kmem_cache
*s
,
3144 char *buf
, unsigned long flags
)
3146 unsigned long total
= 0;
3150 unsigned long *nodes
;
3151 unsigned long *per_cpu
;
3153 nodes
= kzalloc(2 * sizeof(unsigned long) * nr_node_ids
, GFP_KERNEL
);
3154 per_cpu
= nodes
+ nr_node_ids
;
3156 for_each_possible_cpu(cpu
) {
3157 struct page
*page
= s
->cpu_slab
[cpu
];
3161 node
= page_to_nid(page
);
3162 if (flags
& SO_CPU
) {
3165 if (flags
& SO_OBJECTS
)
3176 for_each_online_node(node
) {
3177 struct kmem_cache_node
*n
= get_node(s
, node
);
3179 if (flags
& SO_PARTIAL
) {
3180 if (flags
& SO_OBJECTS
)
3181 x
= count_partial(n
);
3188 if (flags
& SO_FULL
) {
3189 int full_slabs
= atomic_read(&n
->nr_slabs
)
3193 if (flags
& SO_OBJECTS
)
3194 x
= full_slabs
* s
->objects
;
3202 x
= sprintf(buf
, "%lu", total
);
3204 for_each_online_node(node
)
3206 x
+= sprintf(buf
+ x
, " N%d=%lu",
3210 return x
+ sprintf(buf
+ x
, "\n");
3213 static int any_slab_objects(struct kmem_cache
*s
)
3218 for_each_possible_cpu(cpu
)
3219 if (s
->cpu_slab
[cpu
])
3222 for_each_node(node
) {
3223 struct kmem_cache_node
*n
= get_node(s
, node
);
3225 if (n
->nr_partial
|| atomic_read(&n
->nr_slabs
))
3231 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
3232 #define to_slab(n) container_of(n, struct kmem_cache, kobj);
3234 struct slab_attribute
{
3235 struct attribute attr
;
3236 ssize_t (*show
)(struct kmem_cache
*s
, char *buf
);
3237 ssize_t (*store
)(struct kmem_cache
*s
, const char *x
, size_t count
);
3240 #define SLAB_ATTR_RO(_name) \
3241 static struct slab_attribute _name##_attr = __ATTR_RO(_name)
3243 #define SLAB_ATTR(_name) \
3244 static struct slab_attribute _name##_attr = \
3245 __ATTR(_name, 0644, _name##_show, _name##_store)
3247 static ssize_t
slab_size_show(struct kmem_cache
*s
, char *buf
)
3249 return sprintf(buf
, "%d\n", s
->size
);
3251 SLAB_ATTR_RO(slab_size
);
3253 static ssize_t
align_show(struct kmem_cache
*s
, char *buf
)
3255 return sprintf(buf
, "%d\n", s
->align
);
3257 SLAB_ATTR_RO(align
);
3259 static ssize_t
object_size_show(struct kmem_cache
*s
, char *buf
)
3261 return sprintf(buf
, "%d\n", s
->objsize
);
3263 SLAB_ATTR_RO(object_size
);
3265 static ssize_t
objs_per_slab_show(struct kmem_cache
*s
, char *buf
)
3267 return sprintf(buf
, "%d\n", s
->objects
);
3269 SLAB_ATTR_RO(objs_per_slab
);
3271 static ssize_t
order_show(struct kmem_cache
*s
, char *buf
)
3273 return sprintf(buf
, "%d\n", s
->order
);
3275 SLAB_ATTR_RO(order
);
3277 static ssize_t
ctor_show(struct kmem_cache
*s
, char *buf
)
3280 int n
= sprint_symbol(buf
, (unsigned long)s
->ctor
);
3282 return n
+ sprintf(buf
+ n
, "\n");
3288 static ssize_t
aliases_show(struct kmem_cache
*s
, char *buf
)
3290 return sprintf(buf
, "%d\n", s
->refcount
- 1);
3292 SLAB_ATTR_RO(aliases
);
3294 static ssize_t
slabs_show(struct kmem_cache
*s
, char *buf
)
3296 return slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
);
3298 SLAB_ATTR_RO(slabs
);
3300 static ssize_t
partial_show(struct kmem_cache
*s
, char *buf
)
3302 return slab_objects(s
, buf
, SO_PARTIAL
);
3304 SLAB_ATTR_RO(partial
);
3306 static ssize_t
cpu_slabs_show(struct kmem_cache
*s
, char *buf
)
3308 return slab_objects(s
, buf
, SO_CPU
);
3310 SLAB_ATTR_RO(cpu_slabs
);
3312 static ssize_t
objects_show(struct kmem_cache
*s
, char *buf
)
3314 return slab_objects(s
, buf
, SO_FULL
|SO_PARTIAL
|SO_CPU
|SO_OBJECTS
);
3316 SLAB_ATTR_RO(objects
);
3318 static ssize_t
sanity_checks_show(struct kmem_cache
*s
, char *buf
)
3320 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DEBUG_FREE
));
3323 static ssize_t
sanity_checks_store(struct kmem_cache
*s
,
3324 const char *buf
, size_t length
)
3326 s
->flags
&= ~SLAB_DEBUG_FREE
;
3328 s
->flags
|= SLAB_DEBUG_FREE
;
3331 SLAB_ATTR(sanity_checks
);
3333 static ssize_t
trace_show(struct kmem_cache
*s
, char *buf
)
3335 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_TRACE
));
3338 static ssize_t
trace_store(struct kmem_cache
*s
, const char *buf
,
3341 s
->flags
&= ~SLAB_TRACE
;
3343 s
->flags
|= SLAB_TRACE
;
3348 static ssize_t
reclaim_account_show(struct kmem_cache
*s
, char *buf
)
3350 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RECLAIM_ACCOUNT
));
3353 static ssize_t
reclaim_account_store(struct kmem_cache
*s
,
3354 const char *buf
, size_t length
)
3356 s
->flags
&= ~SLAB_RECLAIM_ACCOUNT
;
3358 s
->flags
|= SLAB_RECLAIM_ACCOUNT
;
3361 SLAB_ATTR(reclaim_account
);
3363 static ssize_t
hwcache_align_show(struct kmem_cache
*s
, char *buf
)
3365 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_HWCACHE_ALIGN
));
3367 SLAB_ATTR_RO(hwcache_align
);
3369 #ifdef CONFIG_ZONE_DMA
3370 static ssize_t
cache_dma_show(struct kmem_cache
*s
, char *buf
)
3372 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_CACHE_DMA
));
3374 SLAB_ATTR_RO(cache_dma
);
3377 static ssize_t
destroy_by_rcu_show(struct kmem_cache
*s
, char *buf
)
3379 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_DESTROY_BY_RCU
));
3381 SLAB_ATTR_RO(destroy_by_rcu
);
3383 static ssize_t
red_zone_show(struct kmem_cache
*s
, char *buf
)
3385 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_RED_ZONE
));
3388 static ssize_t
red_zone_store(struct kmem_cache
*s
,
3389 const char *buf
, size_t length
)
3391 if (any_slab_objects(s
))
3394 s
->flags
&= ~SLAB_RED_ZONE
;
3396 s
->flags
|= SLAB_RED_ZONE
;
3400 SLAB_ATTR(red_zone
);
3402 static ssize_t
poison_show(struct kmem_cache
*s
, char *buf
)
3404 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_POISON
));
3407 static ssize_t
poison_store(struct kmem_cache
*s
,
3408 const char *buf
, size_t length
)
3410 if (any_slab_objects(s
))
3413 s
->flags
&= ~SLAB_POISON
;
3415 s
->flags
|= SLAB_POISON
;
3421 static ssize_t
store_user_show(struct kmem_cache
*s
, char *buf
)
3423 return sprintf(buf
, "%d\n", !!(s
->flags
& SLAB_STORE_USER
));
3426 static ssize_t
store_user_store(struct kmem_cache
*s
,
3427 const char *buf
, size_t length
)
3429 if (any_slab_objects(s
))
3432 s
->flags
&= ~SLAB_STORE_USER
;
3434 s
->flags
|= SLAB_STORE_USER
;
3438 SLAB_ATTR(store_user
);
3440 static ssize_t
validate_show(struct kmem_cache
*s
, char *buf
)
3445 static ssize_t
validate_store(struct kmem_cache
*s
,
3446 const char *buf
, size_t length
)
3449 validate_slab_cache(s
);
3454 SLAB_ATTR(validate
);
3456 static ssize_t
shrink_show(struct kmem_cache
*s
, char *buf
)
3461 static ssize_t
shrink_store(struct kmem_cache
*s
,
3462 const char *buf
, size_t length
)
3464 if (buf
[0] == '1') {
3465 int rc
= kmem_cache_shrink(s
);
3475 static ssize_t
alloc_calls_show(struct kmem_cache
*s
, char *buf
)
3477 if (!(s
->flags
& SLAB_STORE_USER
))
3479 return list_locations(s
, buf
, TRACK_ALLOC
);
3481 SLAB_ATTR_RO(alloc_calls
);
3483 static ssize_t
free_calls_show(struct kmem_cache
*s
, char *buf
)
3485 if (!(s
->flags
& SLAB_STORE_USER
))
3487 return list_locations(s
, buf
, TRACK_FREE
);
3489 SLAB_ATTR_RO(free_calls
);
3492 static ssize_t
defrag_ratio_show(struct kmem_cache
*s
, char *buf
)
3494 return sprintf(buf
, "%d\n", s
->defrag_ratio
/ 10);
3497 static ssize_t
defrag_ratio_store(struct kmem_cache
*s
,
3498 const char *buf
, size_t length
)
3500 int n
= simple_strtoul(buf
, NULL
, 10);
3503 s
->defrag_ratio
= n
* 10;
3506 SLAB_ATTR(defrag_ratio
);
3509 static struct attribute
* slab_attrs
[] = {
3510 &slab_size_attr
.attr
,
3511 &object_size_attr
.attr
,
3512 &objs_per_slab_attr
.attr
,
3517 &cpu_slabs_attr
.attr
,
3521 &sanity_checks_attr
.attr
,
3523 &hwcache_align_attr
.attr
,
3524 &reclaim_account_attr
.attr
,
3525 &destroy_by_rcu_attr
.attr
,
3526 &red_zone_attr
.attr
,
3528 &store_user_attr
.attr
,
3529 &validate_attr
.attr
,
3531 &alloc_calls_attr
.attr
,
3532 &free_calls_attr
.attr
,
3533 #ifdef CONFIG_ZONE_DMA
3534 &cache_dma_attr
.attr
,
3537 &defrag_ratio_attr
.attr
,
3542 static struct attribute_group slab_attr_group
= {
3543 .attrs
= slab_attrs
,
3546 static ssize_t
slab_attr_show(struct kobject
*kobj
,
3547 struct attribute
*attr
,
3550 struct slab_attribute
*attribute
;
3551 struct kmem_cache
*s
;
3554 attribute
= to_slab_attr(attr
);
3557 if (!attribute
->show
)
3560 err
= attribute
->show(s
, buf
);
3565 static ssize_t
slab_attr_store(struct kobject
*kobj
,
3566 struct attribute
*attr
,
3567 const char *buf
, size_t len
)
3569 struct slab_attribute
*attribute
;
3570 struct kmem_cache
*s
;
3573 attribute
= to_slab_attr(attr
);
3576 if (!attribute
->store
)
3579 err
= attribute
->store(s
, buf
, len
);
3584 static struct sysfs_ops slab_sysfs_ops
= {
3585 .show
= slab_attr_show
,
3586 .store
= slab_attr_store
,
3589 static struct kobj_type slab_ktype
= {
3590 .sysfs_ops
= &slab_sysfs_ops
,
3593 static int uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
3595 struct kobj_type
*ktype
= get_ktype(kobj
);
3597 if (ktype
== &slab_ktype
)
3602 static struct kset_uevent_ops slab_uevent_ops
= {
3603 .filter
= uevent_filter
,
3606 decl_subsys(slab
, &slab_ktype
, &slab_uevent_ops
);
3608 #define ID_STR_LENGTH 64
3610 /* Create a unique string id for a slab cache:
3612 * :[flags-]size:[memory address of kmemcache]
3614 static char *create_unique_id(struct kmem_cache
*s
)
3616 char *name
= kmalloc(ID_STR_LENGTH
, GFP_KERNEL
);
3623 * First flags affecting slabcache operations. We will only
3624 * get here for aliasable slabs so we do not need to support
3625 * too many flags. The flags here must cover all flags that
3626 * are matched during merging to guarantee that the id is
3629 if (s
->flags
& SLAB_CACHE_DMA
)
3631 if (s
->flags
& SLAB_RECLAIM_ACCOUNT
)
3633 if (s
->flags
& SLAB_DEBUG_FREE
)
3637 p
+= sprintf(p
, "%07d", s
->size
);
3638 BUG_ON(p
> name
+ ID_STR_LENGTH
- 1);
3642 static int sysfs_slab_add(struct kmem_cache
*s
)
3648 if (slab_state
< SYSFS
)
3649 /* Defer until later */
3652 unmergeable
= slab_unmergeable(s
);
3655 * Slabcache can never be merged so we can use the name proper.
3656 * This is typically the case for debug situations. In that
3657 * case we can catch duplicate names easily.
3659 sysfs_remove_link(&slab_subsys
.kobj
, s
->name
);
3663 * Create a unique name for the slab as a target
3666 name
= create_unique_id(s
);
3669 kobj_set_kset_s(s
, slab_subsys
);
3670 kobject_set_name(&s
->kobj
, name
);
3671 kobject_init(&s
->kobj
);
3672 err
= kobject_add(&s
->kobj
);
3676 err
= sysfs_create_group(&s
->kobj
, &slab_attr_group
);
3679 kobject_uevent(&s
->kobj
, KOBJ_ADD
);
3681 /* Setup first alias */
3682 sysfs_slab_alias(s
, s
->name
);
3688 static void sysfs_slab_remove(struct kmem_cache
*s
)
3690 kobject_uevent(&s
->kobj
, KOBJ_REMOVE
);
3691 kobject_del(&s
->kobj
);
3695 * Need to buffer aliases during bootup until sysfs becomes
3696 * available lest we loose that information.
3698 struct saved_alias
{
3699 struct kmem_cache
*s
;
3701 struct saved_alias
*next
;
3704 struct saved_alias
*alias_list
;
3706 static int sysfs_slab_alias(struct kmem_cache
*s
, const char *name
)
3708 struct saved_alias
*al
;
3710 if (slab_state
== SYSFS
) {
3712 * If we have a leftover link then remove it.
3714 sysfs_remove_link(&slab_subsys
.kobj
, name
);
3715 return sysfs_create_link(&slab_subsys
.kobj
,
3719 al
= kmalloc(sizeof(struct saved_alias
), GFP_KERNEL
);
3725 al
->next
= alias_list
;
3730 static int __init
slab_sysfs_init(void)
3732 struct kmem_cache
*s
;
3735 err
= subsystem_register(&slab_subsys
);
3737 printk(KERN_ERR
"Cannot register slab subsystem.\n");
3743 list_for_each_entry(s
, &slab_caches
, list
) {
3744 err
= sysfs_slab_add(s
);
3748 while (alias_list
) {
3749 struct saved_alias
*al
= alias_list
;
3751 alias_list
= alias_list
->next
;
3752 err
= sysfs_slab_alias(al
->s
, al
->name
);
3761 __initcall(slab_sysfs_init
);